Invertebrate pests, such as insects, acaridae and nematode pests destroy growing and harvested crops and attack wooden dwelling and commercial structures, causing large economic loss to the food supply and to property. While a large number of pesticidal agents are known, due to the ability of target pests to develop resistance to said agents, there is an ongoing need for new agents for combating animal pests. In particular, animal pests such as insects and acaridae are difficult to be effectively controlled.
EP 259738 discloses compounds of the formula A, which have insecticidal activity:

where W is a substituted pyridyl radical or a 5- or 6-membered heterocyclic radical, R is hydrogen or alkyl, T together with the atoms to which it is bound forms a 5- or 6-membered heterocyclic ring, Y is inter alia a nitrogen atom and Z is an electron withdrawing group selected from nitro and cyano.
Pesticidal compounds, which are similar to those of EP 259738, are known from EP 639569, where the moiety electron withdrawing moiety Z is an electron withdrawing group such as alkoxcarbonyl, arylcarbonyl, heterocyclic carbonyl, C1-C4-alkylsulfonyl, sulfamoyl or C1-C4-acyl.
US 2013/0150414 describe, inter alia, pesticidal compounds of the formula B

wherein Ar is an aryl or 5- or 6-membered heterocyclic group, Ra is hydrogen or alkyl, Y′ is hyddrogen, halogen, a hydroxyl group, an alkyl group or an alkoxy group and Rb is an alkyl group substituted with halogen or an alkoxy group, optionally substituted with halogen.
Pesticidal compounds, which are similar to those of US 2013/0150414, are known from WO 2013/129688.
The pesticidal activity of the compounds is not satisfactory. It is therefore an object of the present invention to provide compounds having a good pesticidal activity, especially against difficult to control insects and acarid pests.